In a food processor, combine the cheddar with the beer, garlic,
mustard and cayenne and blend until smooth. Season the beer cheese with
salt.
Preheat the broiler. Spread the toasts with the beer cheese and
arrange them on a rimmed baking sheet. Broil the toasts 6 inches from
the heat for about 2 minutes, rotating the pan, until the cheese is
bubbling and browned around the edges. Top with tomato slices and serve.